According to the passage, which of the following is NOT mentioned?A.People are not sure of
According to the passage, which of the following is NOT mentioned?
A.People are not sure of the reason why the proportion of test-tube girls to boys is high.
B.Heart defect usually occurs in only 15 out of 60,000 in Australia.
C.Heart defect shows up in one out of nine test-tube babies.
D.The test-tube babies are growing well.